Well, in some 'bleach humans do fanfic' stories, humans might be given the ability to enter the Soul Society without dying first. They could then explore this new world, interact with the different divisions of Soul Reapers, and perhaps even learn some of their techniques. For example, a human could end up in the 11th division and train with the warriors there, leading to all kinds of humorous and action - packed situations.
Some 'bleach gamer fanfic' explore what would happen if the Bleach characters themselves were part of a game world created by humans. So, Ichigo might find himself in a strange digital landscape where he has to figure out the rules of this new world, which are based on the way humans perceive the Bleach universe in their games.
One interesting 'bleach moonlight fanfic' could be about a character's journey under the moonlight in the Bleach universe, perhaps exploring their hidden powers. For example, a story where Ichigo discovers a new form of his Zanpakuto while bathed in moonlight during a battle with a powerful Hollow. Another could focus on the relationship between characters, like Rukia and Renji, and how the moonlight sets a romantic or mysterious backdrop for their interactions.
One interesting antagonist bleach fanfic could be one where the main antagonist has a backstory that makes you sympathize with them. For example, a story that delves into Aizen's past and his motives in a new light, showing that his actions were perhaps a result of a greater, more complex plan for the Soul Society that was misinterpreted. Another could be a fanfic that focuses on the Hollows as the protagonists, turning the traditional view of them as just mindless monsters on its head.
You can try fanfiction.net. It has a large collection of fan - made stories, and there are likely to be some great 'bleach humans do fanfic' among them.
One idea could be to explore an alternate timeline where Ichigo never became a Soul Reaper. Maybe he lives a normal life, but strange spiritual events still occur around him, drawing him into the world of the Hollows and Soul Reapers in a different way. Another idea is to focus on a side character, like Uryu, and tell a story from his perspective during a major arc that we didn't see much of in the original series. For example, his experiences during the Arrancar arc when he was off on his own missions.
One interesting plotline could be the main character using gamer skills to quickly level up in the Bleach universe. For example, they might be able to analyze enemy weaknesses like in a game and use that to their advantage in battles against Hollows or other Soul Reapers.
One interesting concept could be the reincarnation of characters with different powers or personalities. For example, a character who was once a villain in the original 'Bleach' might be reincarnated as a hero, with new abilities and a changed outlook on life.
One interesting concept could be the exploration of the characters' inner struggles during hollowfication. For example, how they deal with the newfound powers and the loss of their humanity in some ways.
A Bleach and One Piece crossover would also be cool. Imagine the Straw Hat Pirates arriving in the Soul Society. Luffy might try to befriend some of the Soul Reapers, and Zoro could have an epic sword - fighting match with one of the more skilled Soul Reapers. Usopp could also be amazed by the different spiritual powers at play.
In a Bleach Candy fanfic, you could have a plot where a mysterious candy starts appearing in Karakura Town. This candy has the ability to make the person who eats it swap bodies with someone else. So, characters like Orihime and Chad end up in each other's bodies and have to figure out how to reverse it. Another idea is that there is a candy that was created by Aizen long ago, and it has been hidden in the Soul Society. When it is finally discovered, it has the power to either destroy or save the entire Soul Society, depending on how it is used. You could also write a fanfic where the mod - souls are given a special candy as a reward for their help, and this candy gives them the ability to take on a more human - like form permanently.